1. Field of the Invention
The present invention relates to a semiconductor device having a heat dissipation layer.
2. Description of the Related Art
Conventionally, semiconductor devices called wafer-level packages (WLPs) have been known, in which bump electrodes for external connection are formed on a wafer, a sealing member is formed around them, and thereafter the wafer is cut into individual semiconductor devices by dicing. In a semiconductor device of this type, a first protective film is formed on the lower surface of a semiconductor substrate which has a plurality of connection pads on the upper surface. A second protective film which has opening portions at portions corresponding to the connection pads of the semiconductor substrate is formed on the upper and side surfaces of the semiconductor substrate. Interconnections are formed on the upper surface of the second protective film and electrically connected to the connection pads of the semiconductor substrate. Columnar electrodes are formed on the upper surfaces of the connection pads of the interconnections. A third protective film is formed on the upper surface of the second protective film including the interconnections around the columnar electrodes (e.g., Jpn. Pat. Appln. KOKAI Publication No. 2001-326299).
In the above-described conventional semiconductor device, the lower, side, and upper surfaces, i.e., all surfaces of the semiconductor substrate are covered with the first to third protective films. For this reason, the protection effect against dust, moisture, and mechanical damage increases. On the other hand, heat generated from the integrated circuit formed on the semiconductor substrate stays in the first to third protective films, resulting in poor heat dissipation effect.